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Industry: Telecom & VoIP

Software development for telecom & VoIP

Carrier grade engineering on FreeSWITCH, Asterisk, Kamailio, and OpenSIPS. We build session border controllers, billing and BSS/OSS systems, contact centres, CPaaS platforms, and AI voice bots that hold up under real call volume. 7+ years deep telecom expertise, TRAI and DLT aware in India, STIR/SHAKEN ready in the US, GDPR and PCI DSS aware in Europe. Pilot from $20,000.

Industry challenges we solve

Telecom is unforgiving. A wrong SDP negotiation drops the call. A missing CDR loses the revenue. A leaked SIP password funds someone else's premium rate fraud overnight. We focus on the failure modes that actually take carriers offline.

One way audio in production. NAT traversal looked fine in staging. The SBC misroutes RTP. Calls connect, nobody hears the customer, support tickets pile up, and every retry costs another minute on the carrier bill.
Toll fraud in the middle of the night. A weak SIP credential on a compromised PBX runs $40,000 of premium rate calls to Latvia in six hours. By the time the carrier alerts you, the money is gone and the dispute is unwinnable.
Billing that does not reconcile. Your CDRs say one minute count, the upstream carrier invoice says another, and finance loses three days a month chasing the gap. Margin disappears into rounding and disputed records.
Contact centres that crumble under load. A campaign launches at 9am, the dialler bursts to 500 concurrent channels, the database starts queueing, agent screens lag, and the regulator notices the abandoned call rate breach before you do.
DLT registration drift in India. A new content template is needed, the DLT portal rejects it, marketing pushes the campaign anyway, the operator filters it as spam, and your sender reputation takes a month to recover.
AI voice bots that feel like 2015 IVRs. Latency is 1.8 seconds, barge in does not work, every misheard digit forces a restart, and customers ask for a human in the first six seconds.
Capabilities

Our telecom & VoIP capabilities

📞

Carrier grade VoIP platforms

FreeSWITCH and Asterisk for media, Kamailio and OpenSIPS for signalling, RTPEngine for media relay. Multi tenant SIP, transcoding, recording, conferencing, and dialplan logic written in Lua, JavaScript, or Python with deterministic call paths.

🛡️

Session border controllers

Custom SBC layers on Kamailio/OpenSIPS, plus integration and extension of Audiocodes, Oracle ACME, and Sansay. Topology hiding, NAT, transcoding offload, fraud rules, Wangiri detection, and per carrier least cost routing.

💳

Telecom billing & BSS/OSS

Real time CDR ingestion, rating engines, prepaid wallets, postpaid invoicing, mediation, dispute reconciliation, and tax handling for telecom levies. Integration with carrier portals, LERG data, NPAC, and Indian DLT systems.

🎧

Contact centres & predictive diallers

Inbound IVR, outbound predictive and progressive diallers with abandoned call rate compliance, agent desktops, call recording with PCI pause/resume, real time wallboards, and CRM integration to Salesforce, HubSpot, Zoho, and bespoke CRMs.

🌐

CPaaS & programmable voice/SMS

Twilio, Vonage, Plivo, MessageBird competitors built from scratch on FreeSWITCH and Kamailio. Number provisioning, programmable IVR via webhooks, SMS/RCS dispatch, recording, transcription, and a billing surface your customers can self serve against.

🤖

AI voice bots & WebRTC

Sub second latency voice agents with Deepgram or AssemblyAI for STT, GPT-4o or Claude for reasoning, ElevenLabs or Cartesia for TTS, and FreeSWITCH bridging the SIP leg. WebRTC clients with LiveKit or Janus for browser to PSTN flows.

Compliance & regulatory considerations

Telecom regulation is jurisdiction specific and the cost of getting it wrong is operator level filtering, regulatory letters, and revoked numbering. We design around the frameworks that actually drive the architecture.

TRAI TCCCPR 2018 DLT (Jio, Airtel, Vi, BSNL) DND scrubbing STIR/SHAKEN (US) FCC Robocall Mitigation GDPR & UK GDPR PCI DSS for billing Ofcom number porting (UK) TRA UAE awareness

India is the most prescriptive market we work in. The TRAI Telecom Commercial Communications Customer Preference Regulations sit on top of the DLT registration regime that every operator implements differently. Our SMS and voice broadcast pipelines scrub against the latest DND register on every send, validate that the PE entity ID, header, and content template ID match what is registered on Jio, Airtel, Vodafone Idea, BSNL, and TataTele, and produce the audit trail TRAI demands during a complaint investigation. For contact centre operators we are familiar with the IP-1 / OSP licensing distinctions and the implications for international transit.

The US robocall regime is now the second most active. We integrate STIR/SHAKEN attestation into FreeSWITCH and Kamailio call legs, sign Identity headers with your STI-CA certificate, verify inbound attestations, and submit the Robocall Mitigation Database certifications the FCC and downstream carriers expect. Originating service providers that are not full carriers can route via an upstream attesting partner; we help you decide which model is cheaper for the call profile you actually run.

Billing that ever sees a card number sits inside PCI DSS. We push tokenisation into Stripe, Adyen, or Razorpay hosted fields so your application servers stay in SAQ A territory rather than SAQ D, and we add PCI pause/resume to call recording so DTMF card capture never persists to disk. GDPR and UK GDPR drive how we handle CDR retention, recorded call retention, and lawful basis for marketing dialling.

Tech stack we use for telecom & VoIP

Battle tested telecom open source where it earns its keep. C and Lua at the dialplan layer, modern stacks above for portals, billing, and AI.

FreeSWITCH + ESL Asterisk + ARI/AGI Kamailio OpenSIPS RTPEngine + RTPProxy Homer SIP capture LiveKit / Janus WebRTC Node.js 20 + TypeScript Go for billing services PostgreSQL + TimescaleDB Kafka + Redis Streams Deepgram, ElevenLabs, GPT-4o
VoIP / Carrier Platform Multi geo CPaaS · 14 weeks · 5 engineers

Multi tenant CPaaS platform on FreeSWITCH and Kamailio

A communications startup needed a Twilio style programmable voice and SMS platform without the per minute markup. We built the SIP signalling layer on Kamailio, the media on a FreeSWITCH cluster behind RTPEngine, and a Node.js control plane that exposed REST and webhook APIs for programmable IVR, recording, and number provisioning. Billing reconciled to the upstream carrier CDRs to the second using a TimescaleDB rating engine. Three carrier interconnects went live in 14 weeks, scaling to 1,200 concurrent channels with sub 100ms post dial delay. Toll fraud was contained through a learned baseline plus hard caps per tenant per hour, blocking three Wangiri attempts in the first month.

1,200Concurrent channels
3Carrier interconnects live
<100msPost dial delay
14 wksConcept to production

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FAQ

Common questions

Telecom is the founding domain at RG INSYS. We have shipped FreeSWITCH, Asterisk, Kamailio, and OpenSIPS deployments in production for 7+ years, ranging from small PBX rollouts to multi tenant carrier platforms doing tens of millions of minutes a month. We have written FreeSWITCH modules in C, Lua dialplan, ESL controllers, Kamailio config, RTPEngine integrations, and OpenSIPS routing logic against real carrier interconnects. We are not a generalist agency that picked up a SIP book last quarter.
Yes. We build SBC layers on top of Kamailio or OpenSIPS for SIP signalling with RTPEngine for media, and we extend commercial SBCs (Audiocodes, Oracle ACME, Sansay) with custom routing, LCR, fraud rules, and least cost engine logic. Common scope: topology hiding, NAT traversal, transcoding offload, DDoS rate limiting, fraud pattern detection (Wangiri, IRSF), and per carrier number translation. We deliver capacity tested designs with documented call paths and failure modes.
Yes. We build to the TRAI Telecom Commercial Communications Customer Preference Regulations 2018, including DLT (Distributed Ledger Technology) header and template registration on Jio, Airtel, Vodafone Idea, BSNL, and TataTele DLT portals. Our SMS and voice broadcast platforms scrub against the DND register on every send, log consent provenance, honour PE entity ID and content template ID requirements, and produce the audit trail TRAI demands during a complaint investigation. We are familiar with the IP-1 / OSP licensing landscape for contact centre operators.
Yes. We integrate STIR/SHAKEN attestation (A, B, C levels) into FreeSWITCH and Kamailio call legs, sign Identity headers with your STI-CA issued certificate, verify inbound Identity headers, and forward attestation status downstream. We also wire the FCC Robocall Mitigation Database submission flow, RMD certification renewals, and the call blocking analytics that TRACED Act compliance is increasingly judged on. Where you are an originating service provider rather than a carrier, we help you decide whether to operate your own CA registration or route via an upstream attesting partner.
Yes. Our preferred path is FreeSWITCH or Asterisk handling the SIP leg, with media bridged into a real time STT (Deepgram, AssemblyAI, Whisper) plus an LLM agent (GPT-4o, Claude, Gemini), and TTS streamed back through ElevenLabs, Azure Neural, or Cartesia. End to end latency lands around 600ms on warm paths, which is the threshold where the conversation actually feels human. We handle barge in, partial transcripts, function calling for CRM lookups, and graceful warm transfer to a human when the bot is unsure.
A focused programmable voice MVP, with inbound DID handling, outbound dialling, recording, basic IVR, webhook events, and a tenant dashboard, typically ships in 8 to 10 weeks on a FreeSWITCH or Asterisk base. We start from $20,000 for a PoC that proves the carrier interconnect, billing model, and key signalling paths under load. Production scale (thousands of concurrent channels, multi region failover, high availability SBC) usually takes a further 6 to 8 weeks of hardening.
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